Tyrosine hydroxylase

Tyrosine hydroxylase (TH) is found in the brain and in the adrenal gland where it catalyses the conversion of tyrosine to 3,4-dihydroxyphenylalanine (DOPA). This is the first and rate limiting step in the biosynthesis of the catecholamines dopamine, norepinephrine and epinephrine (see scheme).

Deficiency in TH has been observed in dopa responsive dystonia and juvenile parkinsonism. A reduced 3,4-dihydroxyphenylalanine production is also observed in Parkinson’s disease. TH is part of the enzyme family of aromatic amino acid hydroxylases.

Structure of the truncated tyrosine hydroxylase containing the catalytic and tetramerization domains.

3D structures of Tyrosine hydroxylase
2xsn – TH catalytic domain – human

2toh, 1toh – TH catalytic and tetramerization domains - rat

Additional Resources
For additional information, see: Amino Acid Synthesis & Metabolism